#### CHAPTER 13 NUCLEUS

Rate of decay

The total decay rate R of a sample is the number of nuclei disintegrating per unit time.

We can therefore, write,

The decay rate of a sample is called activity. The SI unit for activity is Becquerel

Another unit of activity is curie.

1 curie = 1 Ci = 3.7×1010 decays per second = 3.7×1010 Bq